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Thread: Confused with results of film testing

  1. #1
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    Confused with results of film testing

    Hi all,

    I have got a zone I net density of 0.10 which is what I was looking for, the zone VIII density was 2.10 net density to start with which as you know is cooked so I reduced my development time by 15% which got me to 1.70 net density, I reduced again but it still came out at 1.70. I used the same amount of developer/make and temperature, I agitated exactly the same and no change.

    I don't really want to decrease development time anymore because I'm already at 4min 50 sec @ 20C.

    I was told that 1.30 net density was correct for zone VIII.

    Any advise on what you would do in my situation.

    Cheers, Mike.
    Art is the affirmation of life.

  2. #2
    Peter De Smidt's Avatar
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    Re: Confused with results of film testing

    I see 0.10 above FB+F for Zone I as a minimum. I prefer about 0.15. Regarding Zone VIII density, how are you printing, a condenser enlarger, a diffusion enlarger, or via scanning? For a condenser aim for about 1.25 net density, and for a diffusion enlarger go for about 1.35 net. Try diluting your developer to get your times up a bit.
    "Why can't we all just get along?" President Dale, Mars Attacks

  3. #3

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    Re: Confused with results of film testing

    What film, developer, dilution and development method (inversion, rotary, etc.)? Hard to say without such information. That the 1.70 didn't decrease with reduced development suggests you might be at Dmax for your second and third times.

  4. #4
    ic-racer's Avatar
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    Re: Confused with results of film testing

    What paper? What enlarger? See if your Zone VIII prints to 'just off white.' There is no universal density target for Zone VIII, it is just a ballpark figure.

  5. #5

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    Re: Confused with results of film testing

    Put away the densitometer for a while and try this old method for determining development time and film speed. Don't be surprised if the negative you derive has a Zone VIII of close to 2.1

    Years ago I learned the method to find the correct developing time and EI for any film. I think the source was William Mortensen. Mortensen wrote some excellent books and articles about basic sensitometry. The last time I did this test was when I abandoned Tri-X and switched to HP5+ due to cost about five years ago. I proceed as follows.

    I set up my trays with my favorite developer HC110B (1:31). I pull out a sheet from the package in the dark. and then when the package is sealed again I turn on the room lights. This part of the test is done under the lights. I cut the sheet into five strips and mark them 1-5 by punching holes with a paper punch. Lets say the recommended time is 5:00. I want to see 3:00, 4:00, 5:00, 6:00 and 7:00, so I throw all the strips into the developer and agitate as usual until 3:00 when I move the No.1 strip over to the stop bath. Then I pull No.2 at 4:00, No.3 at 5:00, etc. I fix, wash and dry the strips as usual. What we are looking for is the best usable film DMax value. Obviously the film has been fully exposed! When strips dry lay down a page of news print on a table in good light. Find the strip through which the news print is barely visible. That's your developing time. Now to find the film speed.

    Go outside in unchanging light conditions and expose five sheets and expose one at the manufacturers rating and then the other four at one half a stop and one stop less and one half a stop and one stop more. In the dark, develop them all together for your newly derived time. Contact print them together exposing and developing the paper for maximum usable paper DMax value. Pick out the best-looking contact print and you have your film speed.

    Because my 7:00 negative looked the best on the first test, I did the test again with 7:00 as the central developing time and found that 8:00 was indeed too dense. This HP5+ time was the same as the as the developing time I had been using for Tri-X and film speed was also the same, EI400.

    Many of the last generation of B&W gurus favored a development time of 5:00 for Tri-X and suggested an EI of 64-100. You can do the above test backwards, developing for 5:00 minutes and finding the film speed. I like 100. The difference between negatives exposed at 100 and developed for 5:00 is quite subtle. Both could be considered "normal" or N negatives. The 100 negative has slightly greater shadow and highlight detail that only a careful, knowledgeable viewer could detect. This slight improvement might not be worthwhile trading for two stops in the field.

    From here, if you are still with me, you can derive expansion and contraction schemes for both the 100 and 400 "normal negs". I do this by changing dilution rather than time. Make sure you have at least 1 oz. of the concentrated sauce for each 8X10 sheet or equivalent. For expansion I found that 3/4 oz. concentrate to 31 1/4 ozs. H20 yields an N-1 neg at a one stop loss in film speed and 1/2 oz. concentrate to 31 1/2 ozs. H20 yields an N-2 neg at a two stop loss in film speed. For contractions, 1 1/4 oz. of concentrate to 30 3/4 ozs. H20 yields an N+1 neg at a one stop gain in speed and 1 1/2 ozs. concentrate to 30 1/2 ozs. H20 produces an N+2 negative with a two stop gain in speed.

    If you look at the chart of Tri-X film speed in Phil Davis' BTZS book you can easily pick out the film speed in HC110B 5:00 as EI 64.

  6. #6

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    Re: Confused with results of film testing

    Neat methode Neal, I'll try that sometime.
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  7. #7
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    Re: Confused with results of film testing

    I have realised the mistake I made right from the start. I have mixed developer to stock dilution chart not concentrate, rookie mistake

    I would love love to try your method of testing Neal but I'm using a patison tank, but I will defo try the increase/ decrease of dilution instead of time thanks

    Peter, I'm using a scanner ( have u guessed I have no access to a darkroom)
    What density would u recommend at zones I and VIII for scanning?

    Thank you all for your help much appreciated.


    Mike.
    Art is the affirmation of life.

  8. #8

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    Re: Confused with results of film testing

    Correct me if I'm wrong but if you mixed the developer (powder) to a stock solution then that's different than concentrate. When the developer is in concentrate form it's when the developer is already in liquid form like HC110 or Rodinal. Concentrate would then be diluted to a working strength solution.

  9. #9
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    Re: Confused with results of film testing

    On Kodaks charts they say for stock solution you mix 63ml developer to 1ltr of water but for concentrate it is 30ml developer to 1ltr water so basically my solution was way too strong hence I was getting overly dense zone VIII negs which resulted in me lowering my developing time below the recommended 5mins.

    I have just finished the test again with the correct strength solution and I got 0.10 base + Fog, 0.20 net density @ ISO 75 for zone I (which I will round up to 80 Iso),
    and 1.30 net density @ ISO 75 for zone VIII.

    I have just got to test for the expansion and contraction 1 and 2 stops then I can do a test on the dynamic range that holds detail or is that the same as the density test? I would take photos of a textured subject this time at zones I to IX.
    Then maybe a test on reciprocity failure or could I just use Kodaks reciprocity results?

    Cheers, Mike.
    Art is the affirmation of life.

  10. #10
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    Re: Confused with results of film testing

    Yer I am using a consentrate HC110 developer and I accidentally mixed it to working solution from the figure on the stock solution chart so I was using it 2x too strong a mix.
    Art is the affirmation of life.

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